A nondestructive testing device and method for foundation bolts of power transmission tower

Abstract

A nondestructive testing device and method for power transmission tower anchor bolts, comprising controlling an excitation coil connected to a control module to emit a constant magnetic field to magnetize the anchor bolts; using 9 Hall sensors arranged in a 3×3 matrix and closely attached to the surface of a concrete protective cap to receive the signal parameters of the magnetization magnetic field strength in the detection area, and returning the signal parameters to the control module; using an embedded anchor bolt nut missing defect discrimination model, on-site calculation and analysis of whether there is a nut missing defect in the screw of the power transmission tower anchor bolt. The electromagnetic nondestructive testing device and method can detect nut missing defects in a complex reinforced concrete environment where there are dense rigid materials such as tower foot plates around the power transmission tower anchor bolts and the arrangement is irregular.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission structure safety detection, and in particular to a nondestructive detection device and method for foundation bolts of a power transmission tower. Background Art

[0002] Transmission lines are the key link in the transmission of electric energy, and ensuring the safe operation of transmission towers is the key to ensuring energy supply. The anchor bolts used to fix the foundation and tower legs of the transmission tower are affected by various uncertain factors such as construction workers during the construction process. The anchor bolts of the transmission tower may have a nut missing defect, which makes the connection between the tower and the foundation loose, directly affecting the bearing capacity of the transmission tower, leaving potential hidden dangers for the safe operation of the transmission tower. Eliminating such hidden dangers is of great significance to ensure the safe operation of the entire overhead transmission line.

[0003] The current status of non-destructive testing of concrete steel bars at home and abroad is as follows: Chinese patent document CN114001636A records that Zhang Hong and others invented and developed a reinforced concrete protective layer thickness detection method, detection device and use method, which are used to detect the depth of the steel bars inside the concrete protective layer. The primary coil and secondary coil sensors of the device work in a magnetic coupling resonance state. By comparing the voltage U1 obtained by the secondary coil when actually detecting the concrete surface and the voltage U2 obtained when detecting steel bars at different distances, the depth of the steel bars under actual detection is obtained. This solution has low cost and high detection accuracy, but when faced with a complex ferromagnetic environment such as other steel materials around the steel bars, it is difficult to achieve the expected detection effect. Chinese patent document CN113566692A records a nondestructive testing method for the quality of cable cement protection cover plates invented by Yu Jinshan et al., which is used for nondestructive testing of the position and diameter of steel bars in cable cement protection cover plates. The method obtains a sufficient number of standard component scanning signal waveform diagrams to form a scanning signal envelope diagram, and calculates the distribution characteristics of the waveform signal according to the scanning signal envelope diagram, and then obtains the electromagnetic signal characteristic values ​​Lmax1 and Lmax2 fluctuation errors a corresponding to the steel bar position, and the electromagnetic signal characteristic values ​​Smax1 and Smax2 fluctuation errors b corresponding to the steel bar diameter. By comparing the actual measurement results, it is determined whether the position and diameter of the steel bars in the cover plate are qualified. This method can greatly improve the cover plate detection efficiency when facing the detection of concrete cover plates with sparse steel bar spacing and small ferromagnetic environment interference, but it will be difficult to achieve the desired detection effect when facing the situation where the steel bars are dense and the ferromagnetic environment interference is large. In addition, there is Chinese patent document CN114812477A, ​​which records a method for detecting the spacing of steel bars in a concrete structure wall invented by Lv Danping et al. The method is used to address the problems in the prior art that it is inconvenient to measure the spacing between steel bars, the workload is large, the efficiency is low, and the detection accuracy is extremely poor. The scheme uses a steel bar detector for detection. First, a concrete structure wall is selected. The wall detection part deliberately avoids other metal materials and strong ferromagnetic materials. The steel bar detector is slowly and uniformly moved in a direction perpendicular to the concrete structure wall for scanning until the distributed steel bars are scanned, and then the average is taken for spacing judgment. This scheme is mainly aimed at the detection of steel bar spacing in reinforced concrete when the steel bars are arranged regularly. When the ferromagnetic material structure inside the concrete protective layer is relatively complex and irregular, it is difficult to achieve the expected effect.

[0004] Existing detection technologies are difficult to detect whether there are nut missing defects in the anchor bolts hidden in the concrete protective cap of the tower foundation. When there are nut missing defects in the anchor bolts of in-service transmission towers, it is difficult to detect because the defects are hidden in the concrete protective cap and the nearby ferromagnetic environment is complex. A device and method are proposed that can detect nut missing directly on the surface of the concrete protective cap without excavation. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an electromagnetic nondestructive testing device and method for transmission tower anchor bolts, which can perform nut missing defect detection in a complex reinforced concrete environment where there are dense rigid materials such as tower base plates around the transmission tower anchor bolts and the materials are arranged irregularly.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A nondestructive testing device for anchor bolts of a power transmission tower, the device comprises a top plate and a bottom plate arranged up and down, four lifting guide rails fixedly connected between the top plate and the bottom plate and a lifting plate that lifts up and down are arranged, four servo motors with buckle locking modules are arranged on the lifting plate, servo motors are provided with servo motor gears, the servo motor gears are meshed with racks on the lifting guide rails, a coil driving module is arranged below the lifting plate, a magnetic field transmitting module is arranged in the coil driving module, a Hall sensor is arranged on the bottom plate, and the servo motor, the coil driving module, the magnetic field transmitting module and the Hall sensor are all electrically connected to an operating module on the top plate.

[0008] The bottom plate is provided with a hollow area, and two roller connecting shafts penetrate the hollow area and are respectively connected to the rollers on both sides of the device, and an encoder is arranged on one of the roller connecting shafts.

[0009] The above-mentioned Hall sensors are provided with nine on the bottom plate and arranged in the center of the bottom plate in a 3×3 matrix.

[0010] The top plate, lifting plate, bottom plate, lifting guide rail, servo motor gear, roller connecting shaft and connecting parts mentioned above are all made of non-magnetic materials.

[0011] The above-mentioned operation module is equipped with an AD conversion module, a microprocessing module, an execution module, a storage module, a display module and a key input module. The output end of the AD conversion module is connected to the input end of the microprocessing module, and the input end of the AD conversion module is connected to the Hall sensor and the encoder; the output end of the microprocessing module is connected to the input end of the execution module, and the output end of the execution module is respectively connected to the display module, the servo motor, the coil drive module, the buckle locking drive module and the storage module, and the input end of the microprocessing module is connected to the key input module.

[0012] The above-mentioned nine Hall sensors are arranged in a 3×3 matrix and are numbered 1-1.1 to 1-1.9 vertically, wherein 1-1.1, 1-1.2, and 1-1.3 constitute the left analysis unit of the Hall sensor module, 1-1.4, 1-1.5, and 1-1.6 constitute the middle analysis unit of the Hall sensor module, 1-1.7, 1-1.8, and 1-1.9 constitute the middle analysis unit and the right analysis unit of the Hall sensor module, each Hall sensor is fixed at the center of the bottom plate of the device at a distance S from the adjacent Hall sensor.

[0013] The above-mentioned magnetic field transmitting module is provided with three groups of excitation coils with diameters of R1, R2 and R3 respectively, and each group of coils with diameter parameters is made of copper enameled wire with diameter A wound with B turns, and R1>R2>R3, and the excitation coil is fixed at the center position of the lifting plate.

[0014] The above-mentioned nondestructive testing device is provided with a shell, which is formed by splicing a top layer, a bottom layer and four device side panels (44).

[0015] Using the above-mentioned detection method of a transmission tower anchor bolt nondestructive detection device, the detection steps are as follows:

[0016] Step 1. Clean the fallen leaves, weeds and irregular objects around the concrete protective cap at the foundation of the tower, so that the four sides of the concrete protective cap are flat and free of debris, which is convenient for the mobile detection of the device;

[0017] Step 1. Determine the tower foundation number, anchor bolt number and detection window number; define the tower foundation at the lower left corner as foundation a along the line direction, and mark the remaining foundations as foundation b, foundation c and foundation d in the counterclockwise direction. Mark the four anchor bolts closest to the center of the tower in the four tower foundations according to the center of the tower, and determine these four anchor bolts as No. 1 screws of their respective foundations ①. Then, mark the four bolts farthest from the center of the tower in the four tower foundations according to the center of the tower, and determine these four bolts as No. 4 screws of their respective foundations ④. The remaining two screws of each foundation are determined as No. 2 screws ② and No. 3 screws ③ of their respective foundations. Then, determine the detection window corresponding to the screw number according to the screw number, where No. 1 screw corresponds to detection window Ⅰ, No. 2 screws and No. 3 screws correspond to detection window Ⅱ, and No. 4 screw corresponds to detection window Ⅲ.

[0018] Step 3, select the excitation coil with appropriate diameter; according to the screw and detection window number determined in Step 2, detection window II is used to detect the large diameter coil with an application diameter of R1, detection window III is used to detect the medium diameter coil with an application diameter of R2; detection window I is used to detect the small diameter coil with an application diameter of R3; the operator turns on the device, and then according to the number of the anchor bolt screw to be inspected and the diameter selection method in this step, selects the excitation coil diameter corresponding to the detection window in the display module through the function selection button and confirms it;

[0019] Step 4, scan the detection window; the operator sticks the device to one end of the detection window and the device roller overlaps with the top surface of the foundation. After sticking, according to the display module display "whether to start detection" content, use the function key to select the "start detection" command, and press the "OK" key. When the microprocessor module receives the "start detection" command, it controls the selected excitation coil circuit to close. Under the action of constant current, the excitation coil emits a constant magnetic field. Then the operator slowly and evenly moves the device horizontally to the other end of the detection window to scan and detect the entire detection window. During the device scanning process, the constant magnetic field emitted by the excitation coil will magnetize the scanning area passed by the device. After the scanning is completed, the operator removes the device and lays it flat on the ground, waiting for the display module to issue the next command prompt;

[0020] Step 5, determine the quality of the scanning waveform; the signal waveform processing system embedded in the microprocessor module will perform waveform processing on the magnetizing magnetic field signal after AD conversion and the corresponding position signal to obtain the waveform of the magnetizing magnetic field intensity in the scanning area changing with the distance, and analyze whether the variation range from the lowest point to the highest point of the scanning waveform is less than the limit value B0; if the variation range is less than the limit value B0, it indicates that the magnetizing capacity of the constant magnetic field is insufficient, and it is necessary to perform step (6) scanning waveform enhancement, and the display module prompts the operator "Do you confirm the scanning waveform enhancement?"; if the variation range is greater than B0, it indicates that the magnetizing capacity of the constant magnetic field is sufficient, and the operator performs Step 7 waveform comparison analysis and displays the judgment result;

[0021] Step 6, scanning waveform enhancement; after the operator presses the "OK" button on the key input module to confirm the scanning waveform enhancement, the microprocessor module controls the servo motor to rotate, driving the lifting plate to descend a standard distance d toward the bottom layer; after the servo motor stops and the buckle is locked, the display module displays "magnetic field enhancement completed", and the operator repeats Step 4 and Step 5 until the magnetization capacity of the constant magnetic field is sufficient;

[0022] Step 7, waveform comparison and analysis and display of judgment results; when the analysis units of the Hall sensor pass through the screw, they will sense the magnetic field strength, the storage module records the characteristic waveform, and the microprocessor module uses the embedded waveform comparison and analysis system to compare the actual scanned magnetization magnetic field strength variation waveform with the preset magnetization magnetic field strength variation waveform when the anchor bolt screw has a nut. If the actual waveform characteristics are consistent with the preset waveform characteristics, it can be determined that there is a nut on the anchor bolt screw, and the display module controls the display of "the screw has no nut missing defect" through the microprocessor module. On the contrary, if the actual waveform characteristics are inconsistent with the preset waveform characteristics, it can be determined that there is no nut on the anchor bolt screw, and the display module controls the display of "the screw has a nut missing defect" through the microprocessor module.

[0023] Step 8. The operator opens the device log folder through the key input module, creates a detection file and types: "xxx line xxx transmission tower xxx tower base xxx screw has / does not have nut missing defects"; after the information is entered, press the "Reset" button to reset the lifting plate to the initial position close to the top floor of the device, and finally press the "ON / OFF" button to shut down the device to complete the detection task of the screw.

[0024] The present invention provides a nondestructive detection device and method for power transmission tower anchor bolts, comprising: first, controlling an excitation coil connected to a control module to emit a constant magnetic field to magnetize the anchor bolts; second, using 9 Hall sensors arranged in a 3×3 matrix and closely attached to the surface of a concrete protective cap to receive magnetization magnetic field intensity signal parameters of a detection area, and returning the signal parameters to the control module; third, using an embedded anchor bolt nut missing defect discrimination model to perform on-site calculation and analysis of whether there is a nut missing defect in the screw of the power transmission tower anchor bolt.

[0025] The present invention has the following beneficial effects:

[0026] 1. The device and method of the present invention realize electromagnetic nondestructive detection of whether there is a nut missing defect in the anchor bolt screw of the transmission tower in a complex ferromagnetic environment without destroying the concrete protective cap.

[0027] 2. The device of the present invention can change the constant magnetic field distribution by changing the diameter of the excitation coil and the distance between the excitation coil and the anchor bolt according to the complexity of the actual ferromagnetic environment of the target detection screw, so as to reduce the influence of the complex ferromagnetic environment on the magnetization magnetic field strength of the anchor bolt screw and achieve the purpose of on-site detection and evaluation.

[0028] 3. The present invention provides a method for determining whether a foundation bolt has a nut missing problem by analyzing the waveform of the magnetization magnetic field strength that continuously changes with distance. Compared with only analyzing the magnetic field strength at a few fixed positions, this waveform analysis method makes it more accurate to detect and evaluate whether a foundation bolt has a nut defect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0030] Figure 1 This is a schematic diagram of the foundation bolts of the transmission tower;

[0031] Figure 2 This is the top-level operation panel diagram of the device;

[0032] Figure 3 Provide a logical flow chart for information transfer;

[0033] Figure 4 The overall structure diagram of the device;

[0034] Figure 5 This is a top view of the bottom layer of the device;

[0035] Figure 6 Reference diagram for the screw and detection window numbers;

[0036] Figure 7 It is a waveform diagram showing the change of magnetization magnetic field intensity with distance when there is a nut on the preset anchor bolt screw;

[0037] Figure 8 It is a diagram of the test detection platform in the embodiment;

[0038] Fig. 9 It is a comparison chart of the detection window data when there is a nut missing and when there is no nut missing in the test in the embodiment.

[0039] Wherein: Hall sensor 1, AD conversion module 2, microprocessor module 3, execution module 4, display module 5, servo motor 6, coil drive module 7, buckle locking drive module 8, storage module 9, magnetic field transmission module 10, buckle locking module 11, concrete protection cap 12, detection device 13, nut 14, screw 15, tower main material 16, tower oblique material 17, tower foot plate 18, boot plate 19, stiffening plate 20, washer 21, tower foundation 22, ground 23, device lower frame 24, operation module 25, display module 26, Cable socket interfaces 27, 28, 29, 30, 31, 32, 33, roller 34, encoder 35, top plate 36, lifting plate 37, bottom plate 38, key input module 39, lifting guide rail 40, roller connecting shaft 41, first axis 41-1, second axis 41-2, servo motor gear 42, foundation top surface 43, device side panel 44, lifting layer 45, foundation a No. a, foundation b No. b, foundation c No. c, foundation d No. d, screw No. 1 ①, screw No. 2 ②, screw No. 3 ③, screw No. 4 ④. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0041] like Figure 1 As shown in the figure, a non-destructive testing device for the anchor bolts of a transmission tower is provided, the device includes a top plate 36 and a bottom plate 38 arranged up and down, four lifting guide rails 40 fixedly connected between the top plate 36 and the bottom plate 38 and a lifting plate 37 that lifts up and down are provided, four servo motors 6 with buckle locking modules 11 are provided on the lifting plate 37, a servo motor gear 42 is provided on the servo motor 6, and the servo motor gear 42 is meshed with the rack on the lifting guide rail 40, a coil driving module 7 is provided below the lifting plate 37, a magnetic field transmitting module 10 is provided in the coil driving module 7, a Hall sensor 1 is provided on the bottom plate 38, and the servo motor 6, the coil driving module 7, the magnetic field transmitting module 10 and the Hall sensor 1 are all electrically connected to the operating module 25 on the top plate 36.

[0042] The servo motor 6 drives the lifting plate 37 to perform lifting movement on the lifting guide rail 40 to adjust the distance between the excitation coil in the magnetic field transmitting module 10 and the detection surface, and change the constant magnetic field distribution emitted by the excitation coil. The Hall sensor 1 is used to receive the magnetizing magnetic field intensity. With the help of the anchor bolt nut missing defect discrimination model embedded in the operating module 25, on-site calculation and analysis are performed to determine whether there is a nut missing defect in the anchor bolt screw of the transmission tower.

[0043] like Figure 4 As shown in , the bottom plate 38 is provided with a hollow area, and two roller connecting shafts penetrate the hollow area and are respectively connected to the rollers 34 on both sides of the device, and an encoder 35 is provided on one of the roller connecting shafts.

[0044] The encoder is used to calculate the mileage traveled by the roller 34 .

[0045] like Figure 5 As shown in FIG. 1 , nine Hall sensors 1 are provided on the base plate 38 and are arranged in a 3×3 matrix at the center of the base plate 38 .

[0046] Nine Hall sensors arranged in a 3×3 matrix and attached to the surface of the concrete protective cap are used to receive the magnetization magnetic field intensity signal parameters of the detection area and return the signal parameters to the control module.

[0047] The top plate 36, the lifting plate 37, the bottom plate 38, the lifting guide rail 40, the servo motor gear 42, the roller connecting shaft and the connecting parts are all made of non-magnetic materials.

[0048] By using non-magnetic materials, when the magnetic field transmitting module 10 generates a magnetic field, the device structure will not be magnetized, thereby not affecting the magnetic field strength signal fed back by the anchor bolt screw detected by the Hall sensor 1.

[0049] like Figure 3 As shown in , the above-mentioned operation module 25 is provided with an AD conversion module 2, a microprocessing module 3, an execution module 4, a storage module 9, a display module 5 and a key input module 39. The output end of the AD conversion module 2 is connected to the input end of the microprocessing module 3, and the input end of the AD conversion module 2 is connected to the Hall sensor 1 and the encoder 35; the output end of the microprocessing module 3 is connected to the input end of the execution module 4, and the output end of the execution module 4 is respectively connected to the display module 5, the servo motor 6, the coil driving module 7, the buckle locking driving module 8 and the storage module 9, and the input end of the microprocessing module 3 is connected to the key input module 39.

[0050] like Figure 5 As shown in the figure, the above-mentioned nine Hall sensors 1 are arranged in a 3×3 matrix and are numbered 1-1.1 to 1-1.9 vertically, wherein 1-1.1, 1-1.2, and 1-1.3 constitute the left analysis unit of the Hall sensor module 1, 1-1.4, 1-1.5, and 1-1.6 constitute the middle analysis unit of the Hall sensor module 1, 1-1.7, 1-1.8, and 1-1.9 constitute the middle analysis unit and the right analysis unit of the Hall sensor module 1, each Hall sensor is fixed at the center of the device bottom plate 38 at a distance S from the adjacent Hall sensor.

[0051] The magnetic field transmitting module 10 is provided with three groups of excitation coils with diameters R1, R2 and R3 respectively, and each group of coils with diameter parameters is made of copper enameled wire with diameter A wound with B turns, and R1>R2>R3, and the excitation coil is fixed at the center position of the lifting plate 37.

[0052] The detection depth and detection range of the constant magnetic field are controlled by the diameter of the excitation coil. When detecting defects in the anchor bolt screw, the diameter of the excitation coil needs to be selected according to the actual detection window.

[0053] The above-mentioned nondestructive testing device is provided with a shell, which is composed of a top layer, a bottom layer and four device side panels 44.

[0054] Using the above-mentioned detection method of a transmission tower anchor bolt nondestructive detection device, the detection steps are as follows:

[0055] Step 1, clean the fallen leaves, weeds and irregular objects around the concrete protective cap 12 at the foundation of the tower, so that the four sides of the concrete protective cap 12 are flat and free of debris, which is convenient for the mobile detection of the device;

[0056] Step 2, determine the tower foundation number, anchor bolt screw number and detection window number; define the lower left tower foundation as foundation a along the line direction, and mark the remaining foundations as foundation b, foundation c and foundation d in the counterclockwise direction, mark the four anchor bolts closest to the center of the tower in the four tower foundations according to the center position of the tower, and determine these four anchor bolts as No. 1 screws of their respective foundations ①, then, mark the four bolts farthest from the center of the tower in the four tower foundations according to the center position of the tower, and determine these four bolts as No. 4 screws of their respective foundations ④; the remaining two screws of each foundation are determined as No. 2 screws ② and No. 3 screws ③ of their respective foundations; then determine the detection window corresponding to the screw number according to the screw number, where No. 1 screw corresponds to detection window Ⅰ, No. 2 screws and No. 3 screws correspond to detection window Ⅱ, and No. 4 screw corresponds to detection window Ⅲ;

[0057] Step 3, select an excitation coil with a suitable diameter; according to the screw and detection window number determined in Step 2, detection window II is used to detect the large diameter coil with an application diameter of R1, detection window III is used to detect the medium diameter coil with an application diameter of R2; detection window I is used to detect the small diameter coil with an application diameter of R3; the operator turns on the device, and then selects the excitation coil diameter corresponding to the detection window in the display module 5 through the function selection button according to the number of the anchor bolt screw to be inspected and the diameter selection method in this step and confirms it;

[0058] Step 4, scanning the detection window; the operator sticks the device to one end of the detection window and the device roller 34 overlaps with the base top surface 43. After sticking, according to the display module 5, the "whether to start detection" content is displayed, and the "start detection" command is selected with the function key, and the "OK" key is pressed. When the microprocessor module 3 receives the "start detection" command, it controls the selected excitation coil circuit to be closed. Under the action of the constant current, the excitation coil emits a constant magnetic field. Then the operator slowly and uniformly moves the device horizontally to the other end of the detection window to scan and detect the entire detection window. During the scanning process of the device, the constant magnetic field emitted by the excitation coil will magnetize the scanning area passed by the device. After the scanning is completed, the operator removes the device and lays it flat on the ground, waiting for the display module 5 to issue the next command prompt;

[0059] Step 5, judging the eligibility of the scanning waveform; the signal waveform processing system embedded in the microprocessor module 3 performs waveform processing on the magnetizing magnetic field signal after AD conversion and the corresponding position signal, obtains the waveform of the magnetizing magnetic field intensity changing with the distance in the scanning area, and analyzes whether the variation range from the lowest point to the highest point of the scanning waveform is less than the limit value B0; if the variation range is less than the limit value B0, it indicates that the magnetizing capacity of the constant magnetic field is insufficient, and it is necessary to perform step 6 scanning waveform enhancement, and the display module 5 prompts the operator "whether to confirm the scanning waveform enhancement"; if the variation range is greater than B0, it indicates that the magnetizing capacity of the constant magnetic field is sufficient, and the operator performs Step 7 waveform comparison analysis and displays the judgment result;

[0060] Step 6, scanning waveform enhancement; after the operator presses the "OK" button on the key input module 39 to confirm the scanning waveform enhancement, the microprocessor module 3 controls the servo motor 6 to rotate, driving the lifting plate 37 to descend a standard distance d toward the bottom layer; after the servo motor 6 stops and the buckle is locked, the display module 5 displays "magnetic field enhancement completed", and the operator repeats Step 4 and Step 5 until the magnetization capacity of the constant magnetic field is sufficient;

[0061] Step 7, waveform comparison and analysis and display of determination results; when the analysis units of the Hall sensor pass through the screw rod, they will sense the magnetic field strength, the storage module 9 records the characteristic waveform, and the microprocessor module 3 uses the embedded waveform comparison and analysis system to compare the actual scanned magnetization magnetic field strength variation waveform with the preset magnetization magnetic field strength variation waveform when the anchor bolt screw has a nut. If the actual waveform characteristics are consistent with the preset waveform characteristics, it can be determined that there is a nut on the anchor bolt screw, and the display module 5 controls the display of "the screw has no nut missing defect" through the microprocessor module 3. On the contrary, if the actual waveform characteristics are inconsistent with the preset waveform characteristics, it can be determined that there is no nut on the anchor bolt screw, and the display module 5 controls the display of "the screw has a nut missing defect" through the microprocessor module 3.

[0062] Step 8. The operator opens the device log folder through the key input module 39, creates a detection file and types: "xxx line xxx transmission tower xxx tower base xxx screw has / does not have nut missing defects"; after the information is entered, press the "reset" key to reset the lifting plate 37 to the initial position close to the top floor of the device, and finally press the "ON / OFF" key to shut down the device to complete the detection task of the screw.

[0063] Example:

[0064] A nondestructive testing device for foundation bolts of a power transmission tower comprises an operating panel 25, a Hall sensor module 1, a servo motor 6, a magnetic field transmitting module 10, a buckle locking module 11, an encoder 35, and a roller 34.

[0065] Operation panel 25 Figure 2 As shown, the operation panel 25 is provided with cable socket interfaces 27, 28, 29, 30, 31, 32, 33, and the operation panel 25 has built-in AD conversion module 2, microprocessor module 3, execution module 4, storage module 9, display module 5, and key input module 39; the information transmission logic flow chart is as follows Figure 3 As shown, the output end of the AD conversion module 2 is connected to the input end of the microprocessing module 3, and the input end of the AD conversion module 2 is connected to the Hall sensor 1 and the encoder 35; the output end of the microprocessing module 3 is connected to the input end of the execution module 4, and the output end of the execution module 4 is respectively connected to the display module 5, the storage module 9, the key input module 39, the buckle locking drive module 8, and the coil drive module 7;

[0066] The Hall sensor module 1 is composed of 9 Hall sensors 1-1.1, 1-1.2, 1-1.3, 1-1.4, 1-1.5, 1-1.6, 1-1.7, 1-1.8 and 1-1.9, which are arranged in a 3×3 matrix, wherein the Hall sensors 1-1.1, 1-1.2 and 1-1.3 constitute the left analysis unit of the Hall sensor module 1, the Hall sensors 1-1.4, 1-1.5 and 1-1.6 constitute the middle analysis unit of the Hall sensor module 1, and the Hall sensors 1-1.7, 1-1.8 and 1-1.9 constitute the right analysis unit of the Hall sensor module 1, and each Hall sensor is fixed at the center of the bottom layer of the device at a distance S from the adjacent Hall sensor.

[0067] There are three groups of excitation coils with diameters of R1, R2 and R3 in the magnetic field transmitting module 10, and each group of coils with diameter parameters is made of copper enameled wire with a diameter of A wound with B turns, R1>R2>R3. The excitation coil is fixed at the center position of the lifting plate 37. At the same time, the detection depth and detection range of the constant magnetic field are controlled by the diameter of the excitation coil. When detecting defects in the anchor bolt screw, it is necessary to select the excitation coil diameter according to the actual detection window.

[0068] The coil driving module 7 has three sets of driving circuits, which are respectively connected to each set of excitation coils and are used to drive the excitation coils of corresponding diameters;

[0069] There are 7 cable sockets 27, 28, 29, 30, 31, 32, and 33 in total, wherein the cable sockets 27 and 28 are connected to the servo motor 6, the cable sockets 29 and 30 are connected to the bayonet locking module 11, the cable socket 31 is connected to the Hall sensor module 1, the cable socket 32 ​​is connected to the encoder 35, and the cable socket 33 is connected to the coil drive module 7;

[0070] The encoder 35 is connected to the No. 1 shaft 41-1 of the roller connecting shaft 43. Figure 5 As shown, the movement distance information of the roller 34 is transmitted to the AD conversion module 2 through the cable socket 32;

[0071] The buckle locking driving module 8 is connected to the buckle locking module 11, and is used to drive the buckle locking lifting plate 37 in the buckle locking module 11 to prevent the lifting plate 37 from slipping during the detection process;

[0072] The key input module 39 is as follows Figure 2 As shown, it is provided with numbers and letters, and the "shift" key can be used to convert between the digital input, letter input and Chinese character input modes, so that the operator can input the detection line name, detection tower position number, detection tower base number and detection screw number and other information. At the same time, the key module is also provided with four function selection keys "▶", "◀", "▼", and "▲", an "OK" confirmation key, a "del" delete key, an "ON / OFF" switch key and a "reset" key, wherein the "reset" key is only used to reset the lifting plate 37 to the initial position.

[0073] The storage module 9 is used to store the magnetization magnetic field strength information of the scanning position, the preset magnetization magnetic field strength waveform information, the test results and other data information and the test date, test line name, test tower position number, test tower base number and test screw number input by the operator;

[0074] The display module 5 displays key input information, steering gear operation status, the distance between the lifting plate 37 and the bottom layer, and the results of this electromagnetic nondestructive testing, etc.;

[0075] The operator inputs the selected detection window and the excitation coil diameter through the buttons according to the number of the anchor bolt to be inspected, and sticks the device to one end of the detection window with the bottom surface of the device fitting with the top surface 43 of the foundation. After the sticking is completed, according to the display module showing the content of "whether to start detection", the operator selects the "start detection" command with the function key and presses the "OK" button; when the microprocessor module 3 receives the "start detection" command, it controls the excitation coil circuit of the specified diameter to be closed, and under the action of the constant current, the excitation coil emits a constant magnetic field; then the operator slowly and uniformly moves the device horizontally to the other end of the detection window to complete the scanning detection of the entire detection window; during the scanning process of the device, the constant magnetic field emitted by the excitation coil will magnetize the scanning area passed by the device. Scanning area; during the magnetization process, the Hall sensor 1 will continuously receive the magnetization magnetic field strength signal on the concrete protective cap at a frequency f, and the encoder 35 will also continuously record the movement distance signal of the roller 34 at a frequency f; the two signals are transmitted to the AD conversion module 2 built into the operation panel 25 through the cable sockets 31 and 32; after receiving the analog signal, the AD conversion module 2 will convert it into a digital signal and transmit the converted digital signal to the microprocessing module 3; then the signal waveform processing system embedded in the microprocessing module 3 will perform waveform processing on the converted digital signal to obtain a waveform of the magnetization magnetic field strength in the scanning area varying with the distance; if the waveform of the magnetization magnetic field strength varying with the distance changes from the lowest point B1 to the highest point B3 If the amplitude of the change is less than the limit value B0, it indicates that the magnetizing capacity of the constant magnetic field is insufficient, and the result of "insufficient magnetizing capacity of the constant magnetic field" is displayed. At this time, the operator needs to select the "enhance the magnetizing capacity of the constant magnetic field" command through the function selection button; after receiving the command, the microprocessor module 3 controls the servo motor 6 to rotate, driving the lifting plate 37 in the initial position to drop a standard distance d; after the servo motor 6 stops and the buckle is locked, the operator will perform the above-mentioned detection window scanning operation again; if the amplitude of the change is still less than the limit value B0, the operator needs to continue to control the lifting plate 37 to drop a standard distance d, and continue to repeat the above-mentioned detection window scanning operation until the waveform change amplitude is greater than the limit value B0, and the microprocessor module 3 will magnetize the magnetic field strength The waveform that changes with distance is compared with the waveform that changes with distance of the magnetization magnetic field intensity when there is a nut in the preset anchor bolt screw; if the changing trends of the two are consistent, it can be determined that there is a nut on the anchor bolt screw, and the display module 5 controls the display of "the screw has no nut missing defect" through the microprocessor module 3; on the contrary, if the changing trends of the two are inconsistent, it can be determined that there is no nut on the anchor bolt screw, and the display module 5 controls the display of "the screw has a nut missing defect" through the microprocessor module 3; after the result display is completed, the operator completes the recording and storage of the corresponding detection information of the anchor bolt screw through the key input module 39, and resets the lifting plate 37 to the initial position close to the top layer of the device, and finally shuts down to complete the detection task of the screw.

[0076] The microprocessor module 3 adopts the STM32F407 single-chip microprocessor; it has the advantages of high performance and low power consumption. The good fast processing ability of STM32F407 is used to improve the data processing speed, which can well ensure fast calculation on site and quickly obtain results;

[0077] The display module (5) adopts LCD1602 liquid crystal display screen;

[0078] The execution module 4 is the I / O interface of the microprocessor module 3, and performs signal combination output control through the cable socket on the operation panel 25;

[0079] The servo motor 6 uses four DS33235 model steering gears to drive the lifting plate 37 in the device to move up and down;

[0080] The structure of lifting plate 37 is as follows Figure 4 As shown, the movable distance is D, and the standard movable distance of the servo is set to d. After the device is turned on and before the inspection work is carried out, the layer stays at the initial position close to the top layer;

[0081] The initial position of the lifting plate 37 is as follows: Figure 4 As shown, this position is close to the top layer of the device, and the distance from the bottom layer is Y, Y>D;

[0082] The detection window is due to the blocking of the screw rod by the stiffening plate and the isolation of the screw rod by the boot plate, resulting in only a part of the four sides of the concrete protective cap being available for detection. This method calls these detection areas detection windows.

[0083] The waveform change trend is as follows Figure 7 As shown, when there is a nut on the screw, when the device is close to the screw position, that is, point X2 in the figure, the waveform detected by the analysis units of the Hall sensor will first increase from B1 to B3 and then decrease to B2, that is, the magnetic field intensity corresponding to point X2; when the device is far away from the screw position, the magnetizing magnetic field intensity will increase from B2 to B3 and then decrease to B1.

[0084] Transmission tower foundation bolt foundation diagram Figure 1 As shown, in response to the electromagnetic interference generated by the complex ferromagnetic environment in which the anchor bolts are located, the device changes the constant magnetic field distribution by changing the diameter of the excitation coil and the distance between the excitation coil and the anchor bolts, so as to reduce the influence of the complex ferromagnetic environment on the magnetizing magnetic field strength of the anchor bolts, thereby achieving the purpose of on-site detection and evaluation. It is a method for detecting whether there is a nut missing defect in the anchor bolts of the transmission tower without excavating or damaging the foundation and without affecting the safe operation of the foundation.

[0085] A detection method using a nondestructive detection device for transmission tower anchor bolts, the specific detection steps are as follows:

[0086] 1. The test should be carried out in clear weather and dry environment. Pay attention to clearing irregular objects such as fallen leaves and weeds around the concrete protective cap 12, and ensure that the four sides of the concrete protective cap 12 are flat and free of debris to facilitate the mobile detection of the device;

[0087] 2. Determine the tower foundation number, anchor bolt screw number and detection window number; the screw and detection window numbers refer to the figure as follows Figure 6 As shown, the foundation of the lower left tower is defined as foundation a along the line direction, and the remaining foundations are marked as foundation b, foundation c and foundation d in the counterclockwise direction; the four anchor bolts closest to the center of the tower are marked according to the center position of the tower, and these four anchor bolts are respectively determined as No. 1 screws of their respective foundations; then, the four bolts farthest from the center of the tower are marked according to the center position of the tower, and these four bolts are respectively determined as No. 4 screws of their respective foundations; the remaining two screws of each foundation are respectively determined as No. 2 screws and No. 3 screws of their respective foundations; then, the detection window corresponding to the screw number is determined according to the screw number, wherein No. 1 screw corresponds to detection window I, No. 2 screws and No. 3 screws correspond to detection window II, and No. 4 screw corresponds to detection window III;

[0088] 3. Select an excitation coil with a suitable diameter; Figure 6 The screw and detection window numbers shown are: large detection window II, the ferromagnetic environment interference is smaller than other windows, and it is suitable for detection with a large diameter coil with a diameter of R1; medium detection window III, the ferromagnetic environment interference is moderate compared to other windows, and it is suitable for detection with a medium diameter coil with a diameter of R2; small detection window I, the ferromagnetic environment interference is larger than other windows, and it is suitable for detection with a small diameter coil with a diameter of R3; the operator presses the "ON / OFF" key of the equipment to turn on the equipment, and then selects the excitation coil diameter corresponding to the detection window in the display module through the function selection key according to the number of the anchor bolt to be detected and the above diameter selection method and confirms it;

[0089] 4. Scan the detection window; the operator sticks the device to one end of the detection window and the device roller 34 overlaps with the base top surface 43; after sticking, according to the display module 5 showing "whether to start detection", use the function key to select the "start detection" command, and press the "OK" key; when the microprocessor module 3 receives the "start detection" command, it will control the selected excitation coil circuit to close; under the action of the constant current, the excitation coil emits a constant magnetic field; then the operator slowly and uniformly moves the device horizontally to the other end of the detection window to scan and detect the entire detection window; during the device scanning process, the constant magnetic field emitted by the excitation coil will magnetize the scanning area passed by the device. After the scanning is completed, the operator removes the device and lays it flat on the ground, waiting for the display module 5 to issue the next command prompt;

[0090] 5. Scanning waveform qualification judgment: The signal waveform processing system embedded in the microprocessor module 3 will perform waveform processing on the magnetizing magnetic field signal after AD conversion and the corresponding position signal to obtain the waveform of the magnetizing magnetic field intensity in the scanning area changing with the distance, and analyze whether the variation range from the lowest point to the highest point of the scanning waveform is less than the limit value B0; if the variation range is less than the limit value B0, it indicates that the magnetizing capacity of the constant magnetic field is insufficient, and it is necessary to perform step 6 scanning waveform enhancement, and the display module 5 will prompt the operator "whether to confirm the scanning waveform enhancement"; if the variation range is greater than B0, it indicates that the magnetizing capacity of the constant magnetic field is sufficient, and the operator performs step 7 waveform comparison analysis and displays the judgment result;

[0091] 6. Scanning waveform enhancement; after the operator presses the "OK" button on the key input module 39 to confirm the scanning waveform enhancement, the microprocessor module 3 controls the servo motor 6 to rotate, driving the lifting plate 37 to descend a standard distance d toward the bottom layer; after the servo motor 6 stops and the buckle is locked, the display module 5 displays "magnetic field enhancement completed", and the operator repeats steps 4 and 5 until the magnetization capacity of the constant magnetic field is sufficient;

[0092] 7. Compare and analyze the waveforms and display the judgment results; when there is a nut on the screw of the anchor bolt, the analysis units of the Hall sensor will appear when passing through the screw. Figure 7 The characteristic waveform shown; the microprocessor module 3 compares the actual scanned magnetization magnetic field strength with the distance variation waveform with the preset anchor bolt screw nut when there is a magnetization magnetic field strength with the distance variation waveform, such as Figure 7As shown, if the actual waveform feature is consistent with the preset waveform feature, it can be determined that there is a nut on the anchor bolt screw, and the display module 5 controls the display of "the screw has no nut missing defect" through the microprocessor module 3; conversely, if the actual waveform feature is inconsistent with the preset waveform feature, it can be determined that there is no nut on the anchor bolt screw, and the display module 5 controls the display of "the screw has a nut missing defect" through the microprocessor module 3;

[0093] 8. The operator opens the device log folder through the key input module 39, creates a detection file and types: "xxx line xxx transmission tower xxx tower base xxx screw has / does not have nut missing defects"; after the information is entered, press the "reset" key to reset the lifting plate 37 to the initial position close to the top floor of the device, and finally press the "ON / OFF" key to shut down the device to complete the detection task of the screw.

[0094] Example:

[0095] Establish a transmission tower anchor bolt model, take the transmission tower anchor bolt model as the detection object, and establish Figure 8 The experimental platform shown in the figure ensures that the horizontal height of the coil remains unchanged, slowly translates the coil to scan the window, collects the magnetic field data at the center of the coil and plots it.

[0096] According to the method of the present invention, a coil with a current of 1A, a number of turns of 1000, an inner diameter of 80mm, and an outer diameter of 130mm is selected as a magnetic field emission source to scan the foundation of the anchor bolt with an M30 screw placed therein, and a Gauss meter with a graduation value of 0.01mT is used to detect the magnetic field strength at the center of the coil. The detection data with and without the nut are as follows:

[0097] Table 1: Magnetic field detection data at the center of the coil when the nut is missing or not

[0098]

[0099] As shown in Table 1 and Fig. 9 As shown in , by comparing the magnetic field strength comparison diagram of the detection window with and without nut missing defects, it can be found that when there is a nut on the screw, a characteristic change of up to 4.6mT will occur at the nut position, which is about twice the characteristic change when there is no nut missing defect, and the change rate is greater. When there is no nut on the screw, the magnetic field strength at the screw position changes smoothly, and the magnetic field waveform is smaller than the waveform when there is a nut. This experiment verifies the feasibility and accuracy of the method and device of the present invention.

Claims

1. A detection method for a nondestructive detection device for a transmission tower anchor bolt, characterized in that: The detection device comprises a top plate (36) and a bottom plate (38) arranged vertically, four lifting guide rails (40) fixedly connected between the top plate (36) and the bottom plate (38) and a lifting plate (37) that lifts up and down are provided, four servo motors (6) with buckle locking modules (11) are provided on the lifting plate (37), a servo motor gear (42) is provided on the servo motor (6), the servo motor gear (42) is meshed with a rack on the lifting guide rail (40), a coil drive module (7) is provided below the lifting plate (37), a magnetic field transmitting module (10) is provided in the coil drive module (7), a Hall sensor (1) is provided on the bottom plate (38), and the servo motor (6), the coil drive module (7), the magnetic field transmitting module (10) and the Hall sensor (1) are all electrically connected to the operating module (25) on the top plate (36); The bottom plate (38) is provided with a hollow area, and two roller connecting shafts penetrate the hollow area and are respectively connected to the rollers (34) on both sides of the device, and an encoder (35) is provided on one of the roller connecting shafts; Nine Hall sensors (1) are provided on the base plate (38) and are arranged in a 3×3 matrix at the center of the base plate (38); The top plate (36), the lifting plate (37), the bottom plate (38), the lifting guide rail (40), the servo motor gear (42), the roller connecting shaft and the connecting parts are all made of non-magnetic materials; The operation module (25) is provided with an AD conversion module (2), a microprocessing module (3), an execution module (4), a storage module (9), a display module (5) and a key input module (39); the output end of the AD conversion module (2) is connected to the input end of the microprocessing module (3), and the input end of the AD conversion module (2) is connected to the Hall sensor (1) and the encoder (35); the output end of the microprocessing module (3) is connected to the input end of the execution module (4), and the output end of the execution module (4) is respectively connected to the display module (5), the servo motor (6), the coil drive module (7), the buckle locking drive module (8) and the storage module (9); the input end of the microprocessing module (3) is connected to the key input module (39); The nine Hall sensors (1) are arranged in a 3×3 matrix and are numbered 1-1.1 to 1-1.9 in the vertical direction, wherein 1-1.1, 1-1.2, and 1-1.3 form a left analysis unit of the Hall sensor (1), 1-1.4, 1-1.5, and 1-1.6 form a middle analysis unit of the Hall sensor (1), and 1-1.7, 1-1.8, and 1-1.9 form a right analysis unit of the Hall sensor (1), and each Hall sensor is fixed at the center of the device bottom plate (38) at a distance S from an adjacent Hall sensor; The magnetic field transmitting module (10) is provided with three groups of excitation coils with diameters of R1, R2 and R3 respectively, and each group of coils with diameter parameters is formed by winding B turns of copper enameled wire with a diameter of A, and R1>R2>R3, and the excitation coil is fixed at the center of the lifting plate (37); The steps of the test are: Step 1, clean the fallen leaves, weeds and irregular objects around the concrete protective cap (12) at the foundation of the tower, so that the four sides of the concrete protective cap (12) are flat and free of debris, which is convenient for the mobile detection of the device; Step 2, determine the tower foundation number, anchor bolt screw number and detection window number; define the lower left tower foundation as foundation a (a) along the line direction, and mark the remaining foundations as foundation b (b), foundation c (c) and foundation d (d) in the counterclockwise direction, mark the four anchor bolts closest to the center of the tower in the four tower foundations according to the center position of the tower, and determine these four anchor bolts as screw No. 1 (①) of their respective foundations, then mark the four bolts farthest from the center of the tower in the four tower foundations according to the center position of the tower, and determine these four bolts as screw No. 4 (④) of their respective foundations; the remaining two screws of each foundation are determined as screw No. 2 (②) and screw No. 3 (③) of their respective foundations; then determine the detection window corresponding to the screw number according to the screw number, where screw No. 1 corresponds to detection window I, screw No. 2 and screw No. 3 correspond to detection window II, and screw No. 4 corresponds to detection window III; Step 3, select an excitation coil with a suitable diameter; according to the screw and detection window number determined in Step 2, detection window II is used to detect a large diameter coil with an application diameter of R1, detection window III is used to detect a medium diameter coil with an application diameter of R2, and detection window I is used to detect a small diameter coil with an application diameter of R3; the operator turns on the device, and then selects the excitation coil diameter corresponding to the detection window in the display module (5) and confirms it according to the number of the anchor bolt screw to be inspected and the diameter selection method in this step through the function selection button; Step 4, scanning the detection window; the operator applies the device to one end of the detection window and the device roller (34) overlaps with the base top surface (43). After the application is completed, according to the display module (5) display "whether to start detection" content, use the function key to select the "start detection" command, and press the "OK" key. When the microprocessor module (3) receives the "start detection" command, it controls the selected excitation coil circuit to close. Under the action of the constant current, the excitation coil emits a constant magnetic field. Then the operator slowly moves the device horizontally at a constant speed to the other end of the detection window to scan the entire detection window. During the device scanning process, the constant magnetic field emitted by the excitation coil will magnetize the scanning area passed by the device. After the scanning is completed, the operator removes the device and lays it flat on the ground, waiting for the display module (5) to issue the next command prompt; Step 5, judging the quality of the scanning waveform; the signal waveform processing system embedded in the microprocessor module (3) performs waveform processing on the magnetizing magnetic field signal after AD conversion and the corresponding position signal to obtain a waveform of the magnetizing magnetic field intensity in the scanning area changing with the distance, and analyzes whether the variation range from the lowest point to the highest point of the scanning waveform is less than the limit value B0; if the variation range is less than the limit value B0, it indicates that the magnetizing capacity of the constant magnetic field is insufficient, and it is necessary to perform Step 6 scanning waveform enhancement, and the display module (5) prompts the operator "Do you confirm scanning waveform enhancement?"; if the variation range is greater than B0, it indicates that the magnetizing capacity of the constant magnetic field is sufficient, and the operator performs Step 7 waveform comparison analysis and displays the judgment result; Step 6, scanning waveform enhancement; after the operator presses the "OK" key through the key input module (39) to confirm the scanning waveform enhancement, the microprocessor module (3) controls the servo motor (6) to rotate, driving the lifting plate (37) to descend a standard distance d toward the bottom layer; after the servo motor (6) stops and the buckle is locked, the display module (5) displays "magnetic field enhancement completed", and the operator repeats Step 4 and Step 5 until the magnetizing capacity of the constant magnetic field is sufficient; Step 7, waveform comparison and analysis and display of the determination result; when the analysis units of the Hall sensor pass through the screw rod, they will sense the magnetic field strength, the storage module (9) records the characteristic waveform, and the microprocessing module (3) compares the actual scanned magnetization magnetic field strength variation with distance waveform with the preset magnetization magnetic field strength variation with distance waveform when the anchor bolt screw has a nut through the embedded waveform comparison and analysis system. If the actual waveform characteristics are consistent with the preset waveform characteristics, it can be determined that there is a nut on the anchor bolt screw rod, and the display module (5) controls the display of "the screw rod has no nut missing defect" through the microprocessing module (3). On the contrary, if the actual waveform characteristics are inconsistent with the preset waveform characteristics, it can be determined that there is no nut on the anchor bolt screw rod, and the display module (5) controls the display of "the screw rod has a nut missing defect" through the microprocessing module (3). Step 8. The operator opens the device log folder through the key input module (39), creates a detection file and types in the following information: "xxx line xxx transmission tower xxx tower base xxx screw has / does not have nut missing defect"; after the information is entered, the operator presses the "reset" key to reset the lifting plate (37) to the initial position close to the top floor of the device, and finally presses the "ON / OFF" key to shut down the device, completing the detection task of the screw.

2. The detection method of a nondestructive detection device for foundation bolts of a power transmission tower according to claim 1, characterized in that: The nondestructive testing device is provided with a shell, which is formed by splicing a top layer, a bottom layer and four device side panels (44).

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